There are many underrated Byzantine authors, each deserving a detailed study. One of the most interesting is Nicholas Mesarites, a thirteenth century ecclesiasti. Michael Angold is a well-respected Byzantine scholar and he does an excellent job of introducing and translating the writings of Mesarites. This volume is a welcome addition to the "Translated Texts for Byzantinists" series from Liverpool University Press. Mesarites was only a minor bureaucrat so he ignored the overblown rhetoric that characterized the writings of his contemporaries. None of his writings were "official" commissions. As a result, most of Mesarites' writings survive in a single manuscript. His writing is much more informative than usual. Throw in the fact that Mesarites lived through the turmoil of the political instability of the late twelfth century, the Fourth Crusade, and the anarchy of its aftermath makes anything written during that period a valuable source.
Nicholas Mesarites was from a moderately noble family in Constantinople in the years before the sack of Constantinople in 1204. His career spans the dying years of the Comneni dynasty, the Angeloi emperors, and the traumatic aftermath of the fall of Constantinople. His career was primarily in the church where he served in honourable positions and had the occasion to interact with both the imperial court and the Crusaders. He ended his career as the Bishop of Ephesus in the Byzantine successor kingdom based in Nicaea. His writings encompass a brief historical monograph on a failed coup, a fairly long eulogy on his elder brother, some theology and lots of churchmanship. He is important for understanding the efforts to defend and reconstruct the Orthodox church after the capture of Constantinople, culminating in the restoration of the patriarchate in Nicaea as part of the Empire of Nicaea's efforts to reconstruct the Byzantine state.
Mesarites is credited with a comparatively fresh writing style and that is probably a fair assessment as long as one realizes what he is being compared to. Byzantine literature is not particularly popular these days because it tends to be very much an acquired taste. It can be incredibly mannered and this side of impenetrable in its intertextuality (to use an equally opaque word). Mesarites is rather less so than the writers of the first rank, but this is only a comparative freedom. He can still be hard going at times, especially when he has his rhetorical jets on full.
I found the transcript of a dialogue between Mesarites and the Latin Patriarch Thomas Morosini (195-207), who was trying to impose his authority on the Greeks who remained in Constantinople in 1206, very interesting. It is a very heated exchange. The Greeks eventually established a Patriarchate in exile at Nicaea. Other gems include a description of the Church of the Holy Apostles (75-133) (long since destroyed by the Ottomans), a funeral oration for his older brother John that gives lots of details about Mesarites' family (134-192), and an account of an attempted coup by John the Fat (31-74). There are also some letters and homilies. Only the description of the Church of the Holy Apostles has been previously translated into English and that is long out of print.
Eventually Mesarites migrated to the Empire of Nicaea and became bishop of Ephesus. He died around 1216/17 AD. Nicholas Mesarites is intelligent, patriotic and practical so he comes across as an attractive figure. It turned Mesarites into a person when he had previously been an entry in the Oxford Dictionary of Byzantium. There is a 30-page introduction that provides good background information and every text has its own introduction as well, along with the edition(s) of every text. If you are a fan of Byzantine culture then this book of key sources deserves to be on your shelf.